I was completely engrossed by this and read it in long gulps in a way I almost never do these days. This was a terrific novel: a twentieth century Charlotte Brontë novel, with downtrodden sisters marrying curates and brothers going mad and being led astray by religous nutjobs, not to mention the domineering father. And a sense of Yorkshire not just as moors and wilderness, but also in the solid provincial towns, which reminded me a lot of Shirley.
This is a bildungsroman, following the development of Frederica Potter, and has that great sixties frankness about sex (her first sex is 'neither nice nor nasty, more like incessant Tampax'). Frederica is, as I said in one of the comments previously, the kind of person I would have liked to be when I was 17: spiky and clever, unpopular but not caring about that, and that too reminds me of the Brontës and their stern and spiky heroines (Lucy Snowe, Helen Graham). She's also the only member of her family not cowed by her insane aggressive father, and the family bits are particularly fun: I have a special fondness for mad shouty families in novels.
But as well as being about Frederica on the cusp of adulthood, it's also about a particular period in time: the moment when England moves from post-war austerity towards the colourful decadence of the sixties. It's all set around Queen Elizabeth's coronation and the central event is a play about Elizabeth I put on to mark the occasion. The play is a marvellous anarchic event full of seduction and betrayal: the relations between the different participants become very similar to the goings-on of the real Elizabethan court.
The bit of the book I felt I hadn't really grasped were the weird spiritual 'experiments' carried out by Frederica's brother and his companion the unhinged science teacher. I shall have to reread at some point in the future to see if I get it then.